Evaluation of two commercial bioaugmentation products for enhanced removal of petroleum from a wetland

Abstract

The proximity of petroleum producing and processing facilities to wetlands on the Texas Gulf Coast results in chronic exposure of these sensitive environments to petroleum. In addition, concern exists because of the possibility of exposure from large-scale accidental releases of petroleum. Low-impact repudiation strategies are preferred for wetlands, because traditional repudiation strategies may do more harm than good. This is the third phase in a program developed to evaluate bioremediation as an oil spill response tool. The research is conducted at a facility established following an accidental oil spill on the San Jacinto River in October 1994. Previous research evaluated the intrinsic repudiation of petroleum in a wetland, as well as the use of biostimulation for enhanced biodegradation of petroleum in a wetland. The primary goal of this research was to evaluate the performance of two commercial bioaugmentation products for their ability to enhance bioremediation of petroleum in a wetland. Additional treatments included inorganic nutrients, and an oiled control (intrinsic). The experiment used a controlled application of oil to reduce heterogeneity normally associated with spilled petroleum. The experimental design incorporated full replication and interspersion of treatments in a block design. The first-order biodegradation rate coefficients for the total target saturate and total target aromatic hydrocarbons showed no significant differences between treatments. Comparison of first-order biodegradation rate coefficients for individual hydrocarbon target analyses also showed no differences between the treatments. Although not statistically significant, one of the commercial bioaugmentation products did show consistently higher biodegradation rates for individual target analyses. Comparison of first-order biodegradation rate coefficients for the control treatment showed biodegradation rates comparable with those obtained in previous studies conducted at the site. This research study and the previous studies conducted at the site demonstrate bioremediation can be effective in removing petroleum from the environment. However, further research is necessary to optimize treatment strategies and to increase the understanding of the processes which contribute to bioremediation of petroleum in a wetland.